Dead-Bug Logic Probe In A Magic Marker

December 24, 2016 by Dan Maloney 13 Comments

Logic probes are simple but handy tools that can be had for a couple of bucks. They may not be the sexiest pieces of test gear, nor the most versatile, but they have their place, and building your own logic probe is a great way to understand the tool’s strength and weaknesses.

[Jxnblk]’s take on the logic probe is based on a circuit by [Tony van Roon]. The design hearkens back to a simpler time and is based on components that would have been easy to pick up at any Radio Shack once upon a time. The logic section is centered on the venerable 7400 quad 2-input NAND gate in the classic 14-pin DIP format. The gates light separate LEDs for high and low logic levels, and a 555 timer chip in a one-shot configuration acts as a pulse stretcher to catch transients. The DIP packages lend themselves to quick and dirty “dead bug” construction, and the whole thing fits nicely into a discarded marking pen.

It’s a simple build and a nice form factor for a useful tool, but for an even slimmer package like an old syringe you’ll probably have to go with SMD components. And when you graduate from the simple logic probe, you might want to check out the capabilities of this smart probe.

“What Is My Purpose?” You Amplify And Display Signals.

December 19, 2016 by Kristina Panos 8 Comments

[Andy_Fuentes22] likes to stream music, but is (understandably) underwhelmed by the sound that comes out of his phone. He wanted to build something that not only looks good, but sounds good. Something that could stream music through a Chromecast or a Raspi, but also take auxiliary input. Something awesome, like the Junkbots Sound System.

The ‘bots, named LR-E (Larry) and R8-CHL (Rachel), aren’t just cool pieces of art. They’re both dead-bug-walking bots with an LM386-based amplifier circuit and an AN6884-based VU meter in their transparent, industrial relay bodies. LR-E is the left channel, and his lovely wife is the right channel. The best part is that they are wired into the circuit through their 3.5mm plug legs and the corresponding jacks mounted in the Altoids tin base.

[Andy] built this labor of love from the ground up. He started with some very nice design sketches and took a bazillion pictures along the way. We think it sounds pretty good, but you can judge for yourself after the break. If VU meters are your jam, here’s another that’s built into the speaker.

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Blinktronicator’s POV Sends Our Eyebrows Rocketing Skyward

July 1, 2016 by Mike Szczys 18 Comments

You think you’ve seen everything that there is to see regarding blinking LEDs and then a simple little trick proves you wrong. Our friend [Zach Fredin], aka [Zakqwy], added a pander mode to his blinky board which shows the Hackaday Jolly Wrencher in a Persistence of Vision mode. We love pandering, and obviously you just need to start the mode and wave the board back and forth. But in thinking the obvious you’d be wrong.

blinktronicator-board — Badass deadbug soldering to “fix” a mirrored shift register footprint

In the video after the break [Zach] demonstrates all the features of the blinktronicator and it’s recently finalized firmware. The tiny little board is a USB dongle featuring two buttons and an arc of sixteen LEDs in a rainbow of colors. When we say tiny, we mean it. Those LEDs are 0402 components and the board was small enough (and interesting enough) to receive an honorable mention in the Square Inch Project.

You would think that soldering all those LEDs by hand would be the trick, but [Zach] pulled off a much more difficult feat. Look closely at the image here (or click to embiggen). The two shift register footprints on the prototype were mirrored. He deadbug soldered each of them using — get this — the individual strands from some 28 AWG stranded wire. You sir, get the hardcore hand soldering badge and then some.

Okay, we’ll stop beating around the bush. The ATtiny45 on this board isn’t connected to the USB data lines, they’re only for power. That means, at its heart this is purely a blinking LED project, albeit one that uses the huge range of colors of the PICOLED family of parts. [Zach] did well with just two user inputs, but it’s the very simple POV party trick that really sucked us in. Instead of waving the board around, [Zach] uses a metal offset spatula as a mirror. Moving it back and forth unfolds the carefully timed flashes to draw your message in the air. Such a simple concept, but so satisfying to see it applied in a slightly different way.

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Getting Ugly, Dead Bugs, And Going To Manhattan

May 4, 2016 by Dan Maloney 30 Comments

Back in the 1980s I was a budding electronics geek working in a TV repair shop. I spent most of my time lugging TVs to and from customers, but I did get a little bench time in. By then new TVs were entirely solid-state and built on single PC boards, but every once in a while we’d get an old-timer in with a classic hand-wired tube chassis. I recall turning them over, seeing all the caps and resistors soldered between terminal strips bolted to the aluminum chassis and wondering how it could all possibly work. It all looked so chaotic and unkempt compared to the sleek traces and neat machine-inserted components on a spanking new 19″ Zenith with the System 3 chassis. In a word, the old chassis was just – ugly.

Looking back, I probably shouldn’t have been so judgmental. Despite the decades of progress in PCB design and the democratization of board production thanks to KiCad, OSH Park, and the like, it turns out there’s a lot to be said for ugly methods of circuit construction.

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Adding A Backlight To A Cheap Multimeter

June 11, 2015 by Rick Osgood 15 Comments

We don’t all need super high quality electronic testing gear. Sometimes second-hand or inexpensive equipment is accurate enough to get the job done. Though it can be a bit annoying to miss out on some of those “luxury” features. [Ekriirke] had this problem with his cheap multimeter. He wished the LCD screen had a backlight for easier visibility, so rather than upgrade to a more expensive unit he just added one himself.

After opening up the multimeter [Ekriirke] found that it ran on a single 12V battery. He realized that the simplest thing to do would be to wire up four white LEDs in series. The four LEDs were arranged within the case off to each side of the LCD, one in each corner. The leads were bent at 90 degree angles and soldered together “dead bug” style. Thin strips of copper foil tape were attached to the PCB in such a way that the anode and cathode from the LEDs would make contact when the case was closed back up.

The tape wraps around to the other side of the PCB where there was more room for the next piece of the circuit. A capacitor, resistor, and transistor are used in conjunction with a momentary switch. This circuit allows [Ekriirke] to turn on the light for about ten seconds by pressing the button one time. The circuit also runs through the meter’s dial switch, preventing the LEDs from being turned on while the meter itself is turned off.

[via Reddit]

A Deadbugged GPS/GLONASS/Geiger Counter

April 26, 2015 by Brian Benchoff 38 Comments

So you think you’re pretty good at soldering really tiny parts onto a PCB? You’re probably not as good as [Shibata] who made a GPS/GLONASS and Geiger counter mashup deadbug-style with tiny 0402-sized parts.

The device uses an extremely small GPS/GLONASS receiver, an AVR ATxmega128D3 microcontroller, a standard Nokia phone display and an interesting Geiger tube with a mica window to track its location and the current level of radiation. The idea behind this project isn’t really that remarkable; the astonishing thing is the way this project is put together. It’s held together with either skill or prayer, with tiny bits of magnet wire replacing what would normally be PCB traces, and individual components making up the entire circuit.

While there isn’t much detail on what’s actually going on in this mess of solder, hot glue, and wire, the circuit is certainly interesting. Somehow, [Shibata] is generating the high voltage for the Geiger tube and has come up with a really great way of displaying all the relevant information on the display. It’s a great project that approaches masterpiece territory with some crazy soldering skills.

Thanks [Danny] for sending this one in.

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Volumetric Circuits

September 13, 2014 by Brian Benchoff 47 Comments

Building a circuit Manhattan style with small bits of copper and solder is a skill all its own, and building a prototype dead bug style is close to a black art. [Anderson] is taking it to the next level with his volumetric circuits. Not only is he building a free-form circuit that’s also a one-bit ALU, he’s also designing software to make these sort of circuits easy to design and build.

[Anderson] is calling his 3D circuit design software Pyrite, and it does exactly what it says on the tin: creates three-dimensional, grid-aligned physical circuits. Automating the construction of a circuit is not a trivial task, and soldering all these components together even more so.

With the first prototype of his software, [Anderson] entered the schematic of a simple one bit ALU. The resulting layout was then carefully pieced together with solder and hot glue. It didn’t work, but that’s only because the schematic was wrong. Designing the software is still an incredible accomplishment, and now that [Anderson] has a rudimentary system of automatically designing free form and dead bug circuits, there are a lot of interesting possibilities. Ever wonder if the point to point wiring found in old radios was the most efficient layout? [Anderson] could probably tell you.

You can check out a few videos of [Anderson]’s work below.

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